Alex Demkov, UT-Austin

"Ferroelectric thin films for integrated Si photonics"

Abstract: The von Neumann computer architecture is experiencing difficulties with both scaling and power consumption requirements, and as a result, new computing paradigms are being actively explored. Even more revolutionary would be a complete or partial switch from electrons to photons. Infrared silicon photonics is one possible avenue for realizing such an alternative computing paradigm. This technology will ultimately require integration of active and passive photonic elements on a single chip. One key photonic element is an optical modulator. I will discuss the recent progress in integrating ferroelectric LiNbO₃and BaTiO₃ with silicon photonics for the purpose of fabricating electro-optic modulators exploiting the linear electro-optic effect. I will focus on the fabrication of thick films of ferroelectric perovskite BaTiO₃ capable of providing a robust electro-optic (EO) response via the Pockels effect. The EO response being a tensor property, is very sensitive to crystal microstructure. I will discuss the relation of the film microstructure to its EO properties. EO measurements performed in free space as well as using Si waveguides, deposited atop the film, correlate well with the microstructural analysis and demonstrate the potential of Si-integrated BaTiO₃ for silicon photonics.